Patent Grant
8703750
The present invention relates to mixtures and methods for inducing resistance in plants.
The induction of resistance in plants is a method for controlling diseases, which is of growing interest as it is based on the amplification of a natural process already present in plants by means of the application of products which, in themselves, can also have next to little or no bioactivity.
The natural defense process of plants comprises a complex network of messengers, regulators and genes which provide a large number of responses, said network being defined as an Innate Plant Defense (IPD) network. The functioning of this process is influenced by a number of factors which cannot always be easily controlled. Consequently, one of the problems associated with the induction of resistance in plants is the onset of undesirable effects which economically damage the crop. Large necrosed areas can in fact appear, which reduce the yield of the harvest and/or its economical value.
A possible response of the innate plant defense network does in fact envisage that the plants can synthesize biocide agents with various action mechanisms and morphologically modify the cellular structure, even as far as decreeing the death of the cell (necrosis of the vegetable tissue).
Abiotic stress factors (for example extreme temperatures, drought, salinity), which are not directly connected to phytopathogen infections, can also interfere with the IPD network.
Salicylic acid (SA) plays a key role in IPD. The starting or interruption of a specific IPD, in fact, in addition to the qualitative and quantitative modulation of its response, are an indication of the SA level in vegetable tissues. It has also been recognised that SA is both the switch of a local response and also that of a specific Systemic Acquired Resistance (SAR) which is thought to cause the expression of at least 10 pathogenesis-related proteins (PR). As each of these responses shows a different action mechanism, the induction of plant defense is considered an important means for the anti-resistance strategy (M. Lodovica Gullino, Pierre Leroux and Constance M. Smith, Crop Protection, Vol. 19 (1) (2000) pages 1-11).
The invasion of a vegetable on the part of a phytopathogen stimulates the increase in the SA content which therefore induces the self-defense of the plant against the continuation of the infection underway and allows the infection to be controlled, a control which, however, not always reaches an acceptable level. On the other hand, it is known that the addition of exogenic SA, or a functional analogous product, allows a better, and at times, total control of the oncoming infection, by stimulating preventive responses.
Single products are currently known—salicylic acid and its derivatives, acetyl salicylic acid and its derivatives, 2,6-dichloroisonicotinic acid (INA), S-methyl ester of benzo[1,2,3]thiadiazolyl-7-thiocarboxylic acid (BTH)—which, however, have a limited practical use as they are not able to exert an always reliable control of the disease.
This problem can also arise in genetically modified organisms (GMO), wherein the modification consists in maintaining an SA threshold sufficient for constantly alerting the self-defense mechanisms mediated by the same.
The use of salicylic acid or its functional analogous products, however, can cause undesired side-effects which negatively influence the quality and quantity of the treated crop. These effects are one of the causes which have not allowed a wide exploitation of resistance induction in plants in agronomical practice.
The Applicant has already previously found that salicylic acid, or its functional derivatives, have a synergetic effect with products having a direct fungicidal activity. In particular, inorganic copper compounds, known in the art and already on the market, have already been patented, which have an efficacious synergetic effect with cupric salts of derivatives of salicylic acid, as claimed in international patent application PCT/EP02/12982.
The Applicant has now surprisingly found that certain products which have a scarce or non-existent direct fungicidal activity, when in a mix with salicylic acid or its functional derivatives, are capable of amplifying the activity, also potentially increasing, however, the risk of undesired side-effects.
The Applicant has also found that the addition of specific compounds allows a surprising minimization or absence of the above undesired effects to be obtained.
The Applicant has therefore found blends and an applicative method which allow the agronomic use of IPD in an efficient and safe way, by optionally combining the components of the mixture according to the necessity of amplifying the response and/or obtaining a defense without undesired effects.
An object of the present invention consequently relates to a blend comprising two or more compounds selected from at least two of the following groups:
An object of the present invention is also the use of a blend comprising two or more compounds selected from two of the following groups:
An object of the present invention also relates to the use of two or more compounds selected from at least two of the following groups: one or more compounds belonging to the ESA group and/or one or more compounds belonging to the PRO group and/or one or more compounds belonging to the MOD group, wherein ESA, PRO and MOD have the meanings specified above, applied singly, by means of applicative programs which envisage alternating application, to stimulate the natural defense systems of plants and to induce resistance in plants.
The use of various products for each single group allows the different physico-chemical characteristics of each product to be better exploited, so as to provide specific pharmacokinetics to better modulate its action and make the technology, object of the present invention, more efficient.
The blends thus obtained have such properties as to enable the resistance induction mechanism in plants to be exploited in agronomic practice, thus providing an extremely economically valid and reliable method also under environmental conditions which can cause abiotic stress to the plant (extreme temperatures, drought, salinity, etc. . . . ).
A further object of the present invention therefore relates to a method for stimulating the natural defense systems of plants and inducing resistance in plants, which includes the application of two or more compounds selected from at least two of the following groups: one or more compounds belonging to the ESA group and/or one or more compounds belonging to the PRO group and/or one or more compounds belonging to the MOD group, wherein ESA, PRO and MOD have the meanings specified above, both in a blend with each other or singly, by means of applicative programs which envisage their alternating application.
The method for stimulating the natural defense systems of plants, according to the present invention, is particularly advantageous as it allows the protective activity to be amplified and minimizes the phytotoxic effects associated with the above-mentioned mechanisms, called hypersensitive responses (HR) and providing a significant benefit to the vegetable, which thus remains “immunised” as a whole and more resistant to pathogen agents and various forms of abiotic stress.
In particular the promoting compounds defined PRO, when applied in a mix with salicylic acid or its functional analogous products ESA (exogenous “salicylic acid”) according to the present invention, are capable of providing a synergetic effect, responsible for a surprising amplification of the biocide activity with respect to phytopathogen agents, much higher than the activity expected, as estimated by means of the Limpel formula.
ESA compounds include: salicylic acid, a derivative of salicylic acid and/or a mimetic compound of salicylic acid, or products which exert an analogous function in the plant in the induction process of systemic acquired resistance (SAR, review Ryals et al, 1996 Plant Cell vol. 8, pages 1809-1819) mediated by salicylic acid.
More specifically, the ESA compound of group i) can have the meaning of:
a salicylic compound having formula (I):
wherein:
or ESA can mean a mimetic compound of salicylic acid having formula (IIa) or (IIb):
wherein R1, X and Y have the meanings defined above.
Said compounds having general formula (I), (IIa) and (IIb) can also be present in hydrate form by the coordination of any number of molecules of water, and can be salified by organic bases, such as piperidine, piperazine, morpholine and natural amino acids, such as, for example, lysine, cysteine, serine.
Said compounds (I), (IIa) and (IIb), moreover, when salified with metal cations, are intended as being in any molar ratio between acid and metal, depending on the valence of the metal itself; for example, for a bivalent metal, the acid and metal ratios can be 1:1 or 1:2.
PRO compounds include products which show a scarce or null fungicidal direct activity and which can optionally induce some type of defense or, in any case, physiological perturbation of the plant.
Products defined as PRO can consequently be a wide range of products, of both a natural or synthetic origin, capable of causing such physiological perturbations to the plant as to be able to provoke situations of stress, also non-specific. All resistance inductors can therefore be included, which are known for not being functional analogous products of SA, the same non-virulent or virulent microorganisms, when used in sub-lethal dosages, part of the same which can induce recognition of the pathogen, substances capable of exciting biological systems of the plant causing stress and/or defense responses, also non-specific, and also the use of non-selective chemicals for the plant itself (even herbicides) in sub-lethal dosages.
More specifically, the PRO compound of group ii), subdivided into the sub-groups a-f, can have the following meanings:
MOD compounds include products capable of reducing/eliminating the necrotized surfaces caused by agents involved in hypersensitive responses (HR), or by agents in any case toxic, amplified in their action by SA, possibly strengthened by stress conditions, improving the activity of the phytoiatric mixture and widening its application on site.
As a result of these specific characteristics, MOD compounds can be applied in a blend or alternated with other components of the method object of the present invention, with the first appearance, or preferably for precautionary measures, of symptoms of hypersensitive responses, also on genetically modified plants.
More specifically, the MOD compound of group iii) can have the meaning of:
glutathione (GSH), or a compound capable of favouring accumulation in vegetable tissues, 4-hydroxyproline and its derivatives, allantoine, L-glutamic acid and its derivatives, tert-butylhydroquinone, betaine, cystine, cysteine, or its derivative having formula (III):
wherein:
Said compounds having general formula (III) can also be present in hydrate form, by the coordination of any number of molecules of water, and can be salified by organic bases, such as piperidine, piperazine, morpholine and natural amino acids, such as, for example, lysine.
In particular, the blend comprising one or more MOD compounds, applied together with one or more PRO compounds, in the presence or absence of one or more ESA compounds, exerts these beneficial effects, capable of minimising or avoiding undesired side-effects.
The application of one or more MOD compound together with β-aminobutyric acid (BABA), for example, known for limiting leaf diseases but generating necrosis (Physiological and Molecular Plant Pathology (1994), vol. 44, pages 273-288), produces a reduction in or the elimination of the effect.
In the previously mentioned formulae, C1-C6 alkyl group means a linear or branched C1-C6 alkyl group, possibly substituted, the substituents being the same or different.
Examples of this group are: methyl, ethyl, propyl, isopropyl, tert-butyl, amyl, hexyl.
C1-C6 alkoxyl group means a C1-C6 alkoxyl group in which the aliphatic portion is a C1-C6 alkyl group, as previously defined.
Examples of this group are: methoxyl, ethoxyl, butoxyl.
C1-C6 thioalkyl group means a C1-C6 thioalkyl group in which the aliphatic portion is a C1-C6 alkyl group, as previously defined. Examples of this group are: thiomethyl, thioethyl, thioamyl.
C1-C6 thio-alkoxyl group means a C1-C6 thioalkoxyl group in which the aliphatic portion is a C1-C6 alkyl group, as previously defined. Examples of this group are: thiomethoxyl, thioethoxyl, thiopropoxyl.
C2-C7 carboalkoxyl group means a C2-C7 carboalkoxyl group in which the aliphatic portion is a C1-C6 alkyl group, as previously defined.
Examples of this group are: carboxymethyl, carboxyethyl, carboxypropyl, carboxyhexyl.
Metal cation means a metal cation that can be mono-, di-, tri- or tetra-valent.
Examples of metals are: sodium, lithium, potassium, magnesium, calcium, copper, zinc, iron, manganese.
In the previous definitions, optionally substituted refers to one or more substituents, the same or different, selected from the following groups: halogen atoms, alkyl, alkoxyl, alkylthio, cyano, hydroxy, amino-carbonyl, carboalkoxyl.
Examples of preferred ESA compounds are the following:
Salts of bivalent metals are salts in which the molar ratios acid:metal can be 1:1 or 2:1, for example Cu2+SA2, Cu2+SA.
Examples of PRO compounds are the following:
Examples of MOD compounds are the following:
The compounds indicated as PRO, in particular the PRO compounds pertaining to the sub-group a), (for example titanium dioxide, zinc oxide, silicic acid) are preferably in micronized form with a particle size lower than 1 micron.
An important advantage of the method for stimulating the natural defense systems of plants according to the present invention, consists in allowing the induction of the natural defenses the plant for agronomical purposes, so that the magnitude of the response can be modulated and the response can be reliable with respect to the possible appearance of side-effects which can jeopardize the quality and quantity of the crops treated.
This method therefore envisages applicative programs which involve the application of one or more compounds, among which salicylic acid and its functional homologous products already defined as ESA, blended or alternating with one or more compounds, already defined as PRO, capable of amplifying the response induced by ESA, and/or in a blend or alternating with one or more compounds already defined as MOD, capable of minimizing and/or eliminating undesired side-effects which can cause qualitative or quantitative damage to the crops treated.
The use of blends of one or more PRO compounds, responsible for occasional necrosis when applied to crops under critical biotic and abiotic conditions, is therefore within the spirit of the present invention, in blends or alternated with ESA compounds.
Again within the spirit of the present invention is the use of blends of one or more PRO compounds, responsible for occasional necrosis when applied to crops under critical biotic and abiotic conditions, in blends or alternated with MOD compounds.
Yet again within the spirit of the present invention is the use of blends of one or more ESA compounds, known for inducing SAR, in blends or alternated with MOD compounds.
As mentioned above, an object of the present invention relates to a method for stimulating the natural defense systems of plants and inducing resistance in the plant, which includes the application of two or more compounds selected from at least two of the following groups: one or more compounds belonging to the ESA group and/or one or more compounds belonging to the PRO group and/or one or more compounds belonging to the MOD group, wherein ESA, PRO and MOD have the above-mentioned meanings, either mixed with each other or individually, through applicative programs which envisage their alternating use.
Examples of preferred blends are:
The compounds called ESA, PRO and MOD are products on the market or which can be obtained through the most common synthesis methods known in literature.
The method for stimulating the natural defense systems of plants according of the present invention, allows many fungin and bacterial phytopathogens or viruses to be controlled.
More specifically, the blends according to the present invention have a particularly high fungicidal activity against phytopathogen fungi which attack crops of vines, tobacco, sugar beet, cereals, vegetables, rice, Cucurbitaceae, fruit trees.
Examples of phytopathogen fungi which can be efficaciously fought by means of this technology, are:
This method for stimulating the natural defense systems of plants and inducing resistance in plants, according to the present invention, is capable of exerting a fungicidal action of both a curative and preventive nature.
A further object of the present invention relates to a method for controlling phytopathogen fungi in agricultural crops, which includes the use of two or more compounds selected from at least two of the following groups: one or more compounds belonging to the ESA group and/or one or more compounds belonging to the PRO group and/or one or more compounds belonging to the MOD group, wherein ESA, PRO and MOD have the above-mentioned meanings, both in blends and through applicative programs which envisage their alternated use.
The amount of each compound, selected from those defined as ESA, PRO and MOD, to be applied for obtaining the desired effect can vary according to several factors, such as, for example, the compound used, the crop to be preserved, the type of pathogen, the degree of infection, the climatic conditions, the application method, the formulation adopted.
The dosage of each compound selected from ESA, PRO and MOD, can range from 0.5 g to 5 kg per hectare and normally provide a sufficient control.
The application of this method can be effected on all parts of the plant, for example on the leaves, stems, branches and roots, or on the seed itself before sowing, or on the ground in which the plant grows.
Blends formulated in the form of dry powders, wettable powders, emulsifying concentrates, micro-emulsions, pastes, granulates, solutions, suspensions, etc. . . . can be adopted: the choice of the type of formulation will depend on the specific use.
The blends are prepared in the known way, for example by diluting or dissolving the active substance with a solvent medium and/or a solid diluent, possibly in the presence of surfactants.
Solid diluents or supports which can be used, are for example: silica, kaolin, bentonite, talc, infusorial earth, dolomite, calcium carbonate, magnesia, gypsum, clay, synthetic silicates, attapulgite, sepiolite.
Liquid diluents which can be used, are for example, in addition to water, aromatic organic solvents (xylols or blends of alkylbenzols, chlorobenzenes, etc. . . . ) paraffins (petroleum fractions), alcohols (methanol, propanol, butanol, octanol, glycerine, etc. . . . ), esters (ethyl or isobutyl acetate, etc. . . . ) ketones (cyclohexanone, acetone, acetophenone, isophorone, ethyl amyl ketone, etc. . . . ), amides (N,N-dimethylformamide, N-methylpirrolydone, etc. . . . ).
Sodium salts, calcium salts, triethylamine or triethanolamine, alkylaryl sulphonates, polyethoxylated alkylphenols, polyethoxylated esters of sorbitol, ligninsulphonates, etc. . . . can be used as surfactants.
The blends according to the present invention can also contain special additives for particular purposes, for example adhesive agents, such as gum Arabic, polyvinylalcohol, polyvinylpyrrolidone, etc. . . .
When desired, other compatible active principles can be added to the blend according to the present invention, such as, for example, other fungicides, phytoregulators, antibiotics, herbicides, insecticides, fertilizers.
Preferably, the products already claimed in international patent application PTC/EP02/12982 can be used.
Examples of other fungicides which can be included in the compositions of the invention are: AC-382042, ampropylfos, anilazine, azaconazole, azoxystrobin, benalaxyl (in its racemic form or as an optically active R isomer), benclothiaz, benomyl, bitertanol, blasticidin-S, bromuconazole, bupirimate, buthiobate, captafol, captan, carbendazim, carboxin, carpropamid, chinomethionat, chloroneb, chlorothalonil, chlozolinate, cyazofamid, cymoxanil, cyproconazole, cyprodinil, debacarb, dichlofluanid, dichlone, diclobutrazol, diclomezine, dicloran, dicyclomet, diethofencarb, diphenoconazole, diflumetorim, dimethirimol, dimethomorph, diniconazole, dinocap, dipyrithione, ditalimfos, dithianon, dodemorph, dodine, edifenphos, epoxyconazole, etaconazole, ethaboxam, ethirimol, ethoxyquin, etridiazole, famoxadone, fenamidone, fenaminosulf, fenapanyl, fenarimol, fenbuconazole, fenfuram, fenhexamid, fenpiclonyl, fenpropidin, fenpropimorph, fentin, ferbam, ferimzone, fluazinam, fludioxonyl, flumetover, flumorph, fluoroimide, fluotrimazole, fluoxastrobin, fluquinconazole, flusilazole, flusulfamide, flutolanil, flutriafol, folpet, fosetylaluminium, fuberidazole, furalaxyl, furconazole, guazatine, hexaconazole, hydroxyquinoline sulfate, hymexazol, ICIA0858, imazalil, imibenconazole, iminoctadine, ipconazole, iprobenfos, iprodione, IR5885, isoprothiolane, iprovalicarb, kasugamycin, kresoxim-methyl, mancopper, mancozeb, maneb, mebenil, mepanipyrim, mepronil, metalaxyl, metalaxyl-M, metconazole, methfuroxam, metiram, metsulfovax, MON-65500, myclobutanil, natamycin, nitrothal-isopropyl, nuarimol, ofurace, orisastrobin, oxadixyl, oxycarboxin, pefurazoate, penconazole, pencycuron, pentachlorophenol and its salats, phthalide, piperalin, Bordeaux mixture, polyoxins, probenazole, prochloraz, procymidone, propamocarb, propiconazole, propineb, proquinazid, prothiocarb, prothioconazole, pycoxystrobin, pyracarbolid, pyraclostrobin, pyrazophos, pyrifenox, pyrimethanil, pyroquilon, pyroxyfur, quinacetol, quinazamid, quinconazole, quinoxyfen, quintozene, rabenazole, cuprum hydroxyde, cuprum oxychloride, cuprum sulfate, RH-7281, RPA-407213, simeconazole, spiroxamine, spiromesifen, metominostrobin, streptomycin, SYP-L-190, tebuconazole, tetraconazole, thiabendazole, thicyofen, thifluzamide, thiophanate-methyl, thiram, tioxymid, tolclofos-methyl, tolylfluanid, triadimefon, triadimenol, triarimol, triazbutil, triazoxide, tricyclazole, tridemorf, trifloxystrobin (CGA 279202), triflumizole, triforine, triticonazole, validamycin, vinclozolin, zineb, ziram, sulphur, zoxamide.
These fungicidal compounds are products already on the market or about to be commercialized. Their description can be easily found in technical literature, for example in “The pesticide manual”, 2000, XII edition, British Crop Protection Council Ed.
IR5885 refers to one of the compounds among those claimed in patent application EP-A-1028125.
The concentration of active principle in the above blends can vary within a wide range depending on the active compound, the applications for which it is destined, the environmental conditions and type of formulation adopted.
The concentration of active principle generally ranges from 1 to 90%, preferably from 5 to 50%.
The following examples for the application of the method according to the present invention are provided for illustrative but non-limiting purposes of the present invention.
Table 1-Table 4
Leaves of cultivar Merlot vines, grown in vases, in a conditioned environment (20±1° C., 70% relative humidity), were treated by spraying both sides of the leaves with the blends in question dispersed in an aqueous solution containing 0.3% of tween 20.
After remaining 7 days in a conditioned environment, the plants were infected on the lower side with an aqueous suspension of Plasmorpara viticola spores (200,000 spores per cm3).
The plants were kept in a humidity saturated environment, at 21° C., for the incubation period of the fungus and, at the end of this period (7 days), the fungicidal activity is evaluated according to an evaluation percentage scale from 100 (healthy plant) to 0 (completely infected plant).
From the data indicated in Table 1 and 2, it is possible to verify the synergetic effect of the blends, consisting of the blends being tested, compared with the expected efficacy using the Limpel formula (“Pesticide Science” (1987), vol. 19, pages 309-315):
E=x+y−(xy/100)
wherein:
E is the expected fungicidal activity, in the absence of synergetic effects, from a blend obtained by mixing g.x of the compound X with g.y of the compound Y;
x is the activity of compound X when used alone at a dose of g.x;
y is the activity of compound Y when used alone at a dose of g.y.
When the fungicidal activity found experimentally is greater than the value of E, said activity should be considered as being a synergetic effect.
Undesired effects refer to the appearance of necrosis or leaf decolouring.
♦25
♦25
♦500
♦the doses in ppm refer to the quantity of Active Ingredient.
Undesired effects refer to the appearance of necrosis or leaf decolouring.
Undesired effects refer to the appearance of necrosis or leaf decolouring.
Undesired effects refer to the appearance of necrosis or leaf decolouring.
Table 5
Leaves of cultivar Burley tobacco plants, grown in vases, in a conditioned environment (20±1° C., 70% relative humidity), were treated by spraying both sides of the leaves with the blends in question dispersed in an aqueous solution containing 0.3% of tween 20.
After remaining 7 days in a conditioned environment, the plants were infected on the lower side with an aqueous suspension of Peronospora Tabacina spores (200,000 spores per cm3).
After remaining 24 hours in a humidity saturated environment, at 21° C., the plants were transferred to another conditioned environment for the incubation period of the fungus and, at the end of this period (7 days), the fungicidal activity is evaluated according to an evaluation percentage scale from 100 (healthy plant) to 0 (completely infected plant).
Undesired effects refer to the appearance of necrosis or leaf decolouring.
Table 6
Leaves of cultivar Borlotto of Vigevano bean plants, grown in vases, in a conditioned environment (25±1° C., 60% relative humidity), were treated by spraying both sides of the leaves with the blends in question dispersed in an aqueous solution containing 0.3% of tween 20.
After 7 days in a conditioned environment, the intensity of the necrosis or leaf decolouring is evaluated with an evaluation scale from 100 (healthy plant) to 0 (plant completely infected with necrosis or decoloured).
Table 7
| Number | Date | Country | Kind |
|---|---|---|---|
| MI2004A0402 | Mar 2004 | IT | national |
This application is a divisional application of Ser. No. 10/590,281, filed Aug. 22, 2006 which claims the benefit of PCT/EP2005/001924 filed Feb. 26, 2005, which claims the benefit of Italian application Serial No. MI2004A000402, filed Mar. 1, 2004.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4657928 | Sorenson | Apr 1987 | A |
| 5599529 | Cowie | Feb 1997 | A |
| Number | Date | Country |
|---|---|---|
| WO9933439 | Jul 1999 | WO |
| WO0005954 | Feb 2000 | WO |
| WO 03043971 | May 2003 | WO |
| WO03043971 | May 2003 | WO |
| WO03077654 | Sep 2003 | WO |
| WO03079790 | Oct 2003 | WO |
| Entry |
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| Howard (Occassional Paper Series 7(1):1-14, 2003). |
| International Search Report Dated Jun. 6, 2005. |
| Spletzer M.E. et al. “Salicylic Acid Induces Resistance to Alternaria Solani in Hydroponically Grown Tomato”, Phytopathology, St. Paul. MN (1999) pp. 722-727. |
| Plava T.K. et al., “Salicylic Acid Induced Resistance to Erwinia Carotovora Subsp. Carovora in Tobacco” Mmolecular Plant-Microbe Interactions, APS Press, St Paul, MN vol. 7, No. 3. (1994)pp. 356-363. |
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| Number | Date | Country | |
|---|---|---|---|
| 20100317519 A1 | Dec 2010 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10590281 | US | |
| Child | 12806758 | US |
